1. Field of the Invention
The present invention relates to apparatus for connecting a flexible tube to a spigot, barb, or the like.
2. Description of Related Art
In the food, medical and pharmaceutical industries single use apparatus, or bio-disposable systems, can be used in the preparation of batches of product. Such single use apparatus includes flexible tubing, typically made from silicone, but may be made from other plastics materials, such as thermoplastics. Connections to other pieces of apparatus are commonly made with flanged connectors clamped to each other. The connectors have hollow spigots to which a tube is connected in a fluid tight manner. Connections to other pieces of apparatus can also made using hollow spigots. These spigots are generally provided with barbed ends to retain the tubes.
It is important that this connection between the flexible tube and hollow spigot is fluid tight as fluid leaking between this connection would be lost to the process and when using valuable fluids any loss can be significant. It is particularly important that the connection is stable for the lifetime of the apparatus, because if the connection were to fail, the whole batch may be lost. To prevent disconnection and leaks, the connection is very tight, with the profile of the barb extending slightly beyond the normal diameter of the tube causing slight stretching of the tube around the barb, and therefore making disconnection of the tube from the spigot unlikely to occur. However, this of course makes connecting the tube to the spigot also difficult.
To aid connection, a lubricant, such as alcohol or oil, can be used. However, this can ease both the connection between the tube and the spigot and the disconnection. In addition, the lubricant can seep into the apparatus and contaminate the reaction chemicals and solvents, and the products. Thus it is preferable to avoid the use of such lubricants.
Apparatus has been developed to insert a spigot into a flexible tube, however, these typically incorporate the use of fingers inside the flexible tube to pull the tube open so the spigot can be inserted. While this certainly aids insertion of the spigot into the tube, the use of fingers adds potential contamination into the apparatus and risks damage to both the tube and the spigot. In addition, various types of plastic tubing, in particular thermoplastic tubing, does not return fully to shape once stretched. Thus the use of this type of apparatus to pull the tube open can lead to a permanently enlarged tube and thus a poor connection.